When a display panel is displaying, a voltage is divided due to the presence of resistance of a power signal line, so that the voltage from a power terminal to a voltage receiving terminal of a sub-pixel unit drops or rises. This phenomenon is called an IR Drop (voltage drop due to resistance) phenomenon. The sub-pixel units located at different positions in a pixel array of the display panel have different line lengths to the power terminal, so the effects of IR drop on these sub-pixel units can be different. In order to eliminate the influence of the phenomenon that the effects of IR drop on the sub-pixel units located at different positions are different, it is necessary to compensate for the IR drop in the display panel.